Polynucleotides 2.1.3 b

Question 1

How are hydrogen bonds formed between bases, and how are the phosphodiester bonds between the sugar and phosphate formed?

Answer 1

Through a condensation reaction (removal of H2O)

Question 2

How are hydrogen bonds between bases, and phosphodiester bonds between the sugar-phosphate backbone broken?

Answer 2

Through a hydrolysis reaction (adding H2O)

Question 3

Summary question - describe how nucleotides are joined together in DNA (3 marks)

Answer 3

1 - Phosphodiester bond
2 - Between the phosphate group of one nucleotide and the deoxyribose of the next
3 - Catalysed by DNA polymerase

Question 4

Summary question - describe how two single polynucleotide strands are joined to make a double helix (3 marks)

Answer 4

1 - Hydrogen bonding between base pairs
2 - Complimentary base pairing A-T and C-G
3 - Two antiparallel polynucleotide strands twist to form double helix